1. Field of the Invention
The present invention relates to an image recording apparatus which records an image on a recording medium by moving (subscanning) the recording medium while scanning (main scanning) with a scanner, and to an image recording method.
2. Description of the Related Art
In an image recording apparatus which records an image by carrying out main scanning on a recording medium with a light beam or a writing head while moving (subscanning) the recording medium in a direction substantially perpendicular to a main scanning direction, it is important to decrease a subscanning direction scanning line pitch error, in order to decrease image unevenness.
Conventionally, the subscanning direction scanning line pitch error has been decreased by improving the mechanical accuracy of components of a driving system which moves the recording medium in the subscanning direction, such as a motor or the like.
Alternatively, a feed amount of the recording medium was detected by a detector such as an encoder or the like. On the basis of detection results, the feed amount of the recording medium was feedback-controlled so as to correct the subscanning direction scanning line pitch.
However, in the above-described scanning line pitch correction methods, mechanical accuracy was improved, resulting in higher costs.
Also, in order for a driving means such as a motor or the like, which moves the recording medium, to be able to operate with maximum accuracy by controlling the feed amount of the recording medium so as to be constant, the feed amount of the recording medium was varied by feedback control, which increased the number of error factors. As a result, accuracy tended to decrease.
The present invention was devised in order to solve the above-described problems, and an object of the present invention is to provide an inexpensive image recording apparatus which can correct a subscanning direction scanning line pitch with high accuracy.
According to a first aspect of the invention, an image recording apparatus comprises a scanner which records an image by scanning lines formed by scanning on a recording medium in a predetermined scanning direction; a detector which detects an amount of feed of the recording medium which is fed in a direction substantially perpendicular to the scanning direction of the scanner; and a controller which controls an image recording position of the scanner in a direction of feeding the recording medium in accordance with the feed amount detected by the detector.
According to a second aspect of the invention, an image recording apparatus comprises a scanner which has a light emitting portion and records an image by scanning on a recording medium with a light beam emitted from the light emitting portion in a predetermined scanning direction; a detector which detects a feed amount of the recording medium fed in a direction substantially perpendicular to the scanning direction of the scanner; and a controller which, in accordance with the feed amount detected by the detector, controls an incident angle with respect to the recording medium when a light beam of the scanner irradiates the recording medium.
According to a third aspect of the invention, an image recording method which records an image by scanning a recording medium which is fed in a direction substantially perpendicular to a scanning direction of a scanner comprises the steps of detecting a feed amount of the recording medium; computing a feed error from the feed amount; and correcting an image recording start time of the scanner on the basis of the feed error.